In the Roman era, the coast line lay at the foot of the hill and has withdrawn over the centuries. The theatre therefore once stood near the sea front and was built exploiting the hill slope for the terraces, divided into four sectors by radial stairways. The site was restored to its current state at the end of the 1930s when a series of Medieval houses that had surrounded it in the meantime were eliminated. The theatre’s dimensions are considerable: the maximum diameter is 64 metres, whilst the terraces are 15 metres high and can seat around 6,000 spectators. Constructed between the 1st and 2nd century under the wishes of Tergeste’s Q. Petronius Modestus, State prosecutor for Emperor Trajan, the theatre fell into oblivion following the town’s dwindling importance. It was subsequently rediscovered in 1814 by archaeologists. The nearby Antiquarium contains an ancient necropolis.